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Blue Zones are regions of the world where people have a much higher likelihood of reaching a centenarian age than average. It is estimated that in 2015 the world was home to nearly half a million centenarians, and this number is expected to increase to around 3.7 million by 2050. In 2014, an estimated 72,197 centenarians were alive in the United States, up 43.6% since 2000. In recent years, studies on the factors influencing survival to 100 years have increased dramatically. However, several gaps in our knowledge persist regarding the demographic, environmental, and social contributors to becoming a centenarian. These gaps include factors such as walkability, access to health care, the percentage of working age population by neighborhood, among others.
This study aims to identify Blue Zones in Washington State by examining the likelihood of becoming a centenarian for adults aged 75 and above and to identify social and environmental correlates of healthy aging and longevity.

How the Study was Conducted

A survival analysis of reaching a centenarian age for adults aged 75 years and above was performed using Washington State mortality data from 2011−2015. Models were adjusted for sex, race, education, marital status, and neighborhood level social and environmental variables at the block group level.

What the Study Found

The following characteristics were found to be positively correlated with reaching centenarian age:
  • Higher neighborhood walkability
  • Lower education level
  • Higher socioeconomic status
  • Higher percent of working age population
  • Being white
  • Being female
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Washington State Blue Zones

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Washington state is facing an unprecedented public health challenge with the epidemic of the novel coronavirus and Covid 19, the disease associated with the virus.

The Centers for Disease Control and Prevention (CDC) confirms that some populations are particularly vulnerable to the novel coronavirus and are more likely to develop serious illness and complications from Covid 19, the disease associated with the novel coronavirus.

Specifically, older adults and people who have serious chronic medical conditions, including heart disease, diabetes, and chronic lung disease. In addition, the high degree of transmissibility of the virus means that people living in areas of higher population density may also be at elevated risk.

To better understand how communities in Washington state may differ in their vulnerability to Covid 19, we developed a data visualization that combines key risk factors, using data from the US Census together with data from the Washington Department of Health. We created a census tract (CT)-level index that represents the population vulnerability to Covid 19 as follows. For each census tract in the state (n=1446), we generated an index that combines an indicator of disease burden from diabetes, lung disease, and heart disease in people 65 years and older using mortality data. We also accounted for population density. The disease burden was weighted at 0.75 and the population density was weighted at 0.25. All census tracts with populations older than 65 of less than 20 individuals were not analyzed.

Correlates of Reaching Centenarian Age

Decedents reaching centenarian age (2011 -2015):
2698 (1.8% of deaths >75 years old)
Green Space
Health Care Access
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Municipalities by Centenarian Prevelance
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This study identified several social and environmental factors correlated with becoming a centenarian in Washington State. Some of our findings were consistent with previous research, while some have not been previously explained or explored. Studies such as the one conducted here have numerous implications when it comes to promoting healthy aging and longevity. More research is needed to expand upon these findings in this rapidly growing field.